BOSTON – Jan­uary 10, 2007 – Three North­eastern Uni­ver­sity researchers have pro­posed a new approach for the highly antic­i­pated dis­covery of super­sym­metric par­ti­cles, often called spar­ti­cles. The method­ology, which was pub­lished in the December 21 issue of the Phys­ical Review Let­ters, is based on iden­ti­fying the hier­ar­chical mass pat­terns of spar­ti­cles, which are assumed to exist in a new class of par­ticle physics the­o­ries beyond the Stan­dard Model.

The expected pro­duc­tion of the spar­ti­cles at high energy par­ticle col­liders is strongly cor­re­lated with the spar­ticle mass pat­terns. Pran Nath, Daniel Feldman and Zuowei Liu at North­eastern have uti­lized this cor­re­la­tion to iden­tify the spar­ti­cles at the Large Hadron Col­lider (LHC) at the Euro­pean Orga­ni­za­tion for Nuclear Research in Geneva, Switzer­land. The LHC, which is close to com­ple­tion and set to begin testing within months, will be the world’s largest machine to pro­duce sub-​​atomic par­ti­cles in con­di­tions sim­ilar to when the Big Bang occurred.

“The LHC will allow for the explo­ration of ele­men­tary par­ticle physics at energy scales that have never been probed before,” said Nath, a Matthews Dis­tin­guished Pro­fessor of Physics at North­eastern. “This research has the poten­tial to deepen our under­standing of the nature of physics at its most basic level,” he said.

The 32 spar­ticle masses can stack up in many dif­ferent ways, cre­ating a land­scape of mass hier­ar­chies with numerous pos­sible spar­ticle mass pat­terns. Stacking the first four spar­ti­cles cre­ates a land­scape with close to ten thou­sand pos­si­bil­i­ties, and the land­scape of pos­si­bil­i­ties becomes enor­mous if all 32 spar­ti­cles are included. Only one pos­si­bility out of this incred­ibly large number exists in nature, and that exact pos­si­bility can be dis­cov­ered at the LHC.

The new approach was devel­oped based on the well moti­vated super­gravity model (mSUGRA), which was co-​​authored by Nath in 1982 and is one of the leading can­di­dates for new physics beyond the Stan­dard model. In this new work, the researchers have shown that the number of pos­si­bil­i­ties is reduced enor­mously, down to just six­teen mass pat­terns for the 4 lightest spar­ti­cles, in mSUGRA.

The authors studied the sig­na­ture space of the six­teen pat­terns at the LHC and pro­pose ways in which researchers at the LHC can dis­crim­i­nate among the pat­terns and iden­tify the lowest lying spar­ti­cles. Because the mass hier­ar­chies influ­ence the overall pro­duc­tion rate of var­ious spar­ti­cles, their hier­ar­chical mass pat­tern will deter­mine their signatures.

“We truly stand on the threshold of rev­o­lu­tionary dis­cov­eries in par­ticle physics and the study of pat­terns and pat­tern recog­ni­tion that we pro­pose could be very sig­nif­i­cant in the search for spar­ti­cles, as well as for the dis­covery of new physics at the LHC,” said Nath.

Founded in 1898, North­eastern Uni­ver­sity is a pri­vate research uni­ver­sity located in the heart of Boston. North­eastern is a leader in inter­dis­ci­pli­nary research, urban engage­ment, and the inte­gra­tion of class­room learning with real-​​world expe­ri­ence. The university’s dis­tinc­tive coop­er­a­tive edu­ca­tion pro­gram, where stu­dents alter­nate semes­ters of full-​​time study with semes­ters of paid work in fields rel­e­vant to their pro­fes­sional inter­ests and major, is one of the largest and most inno­v­a­tive in the world. The Uni­ver­sity offers a com­pre­hen­sive range of under­grad­uate and grad­uate pro­grams leading to degrees through the doc­torate in six under­grad­uate col­leges, eight grad­uate schools, and two part-​​time divi­sions. For more infor­ma­tion, please visit www​.north​eastern​.edu.

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